2-12-1
English
Exothermic Reaction
Activity:Activity: Setup Setup
Equipment
This activity uses the neutralization of hydrochloric acid and sodium hydroxide to study heatStandAuto StirrerBeaker (3)
that is given off or absorbed by chemical reactions.Hydrochloric Acid (Solution)Sodium Hydroxide (Solid)Distilled Water
Temperature Measurement Setup (EA-200, graphic scientific calculator,
data communication cable, temperature probe)
Theory
A chemical reaction causes a change in the properties of matter, and always gives off or
Setting Up
u Measure the mass of the hydrochloric acid (aq) and distilled water to be used in theabsorbs heat. The sum of the heat of reaction when a chemical reaction takes place
activity.depends solely on the condition of the matter at the time of the reaction, and is totally
independent of the reaction pathway and the number of steps between the initial state and
u Measure the amount of sodium hydroxide (s) required so the number of its moles is equal
to that of the hydrochloric acid (aq).the final state. This is called HessOs law.
The following illustrates the chemical reaction when sodium chloride (aq) is generated from
u Fix the probe in place at a point between the center of the beaker and the wall of the
sodium hydroxide (s) and hydrochloric acid (aq).
beaker, in a location where it does not strike the stirrerOs magnet, at a depth so it is
sufficiently immersed in the solution.
NaOH(s) + aq = NaOH(aq) + 44.5kJ
NaOH(aq) + HCl(aq) = NaCl(aq) + H2O + 56.4kJ
1Stand
2Auto StirrerNaOH(s) + HCl(aq) = NaCl(aq) + H2O + 100.9kJ
3Beaker
4Temperature Probe (CH1)
5Solution
1Reaction Path 1
6EA-200
2Reaction Path 2
3Energy
4Solvent (Water)
s: solid
aq : aqua
Here, Reaction Path 1 includes the heat of dissolution when sodium hydroxide (s) is
dissolved in distilled water, and the heat of neutralization of sodium hydroxide (aq) and
hydrochloric acid (aq).
Reaction Path 2, on the other hand, consists of the heat of neutralization of sodium
hydroxide (s) and hydrochloric acid (aq).
All of this means that the total heat is the same, regardless of whether or not the pathway
includes a process for dissolving the sodium hydroxide (s), as in Reaction Path 1.
20020601 |
ACEC
